Line protecting and message transmitting system



July 5, 1932. PFIFFNER 1,865,952

LINE PROTECTING AND MESSAGE TRANSMITTING SYSTEM Filed Jan. 23, 1926 5 4a a, q I 6 61 1w; 1 lfi'fifi; 1 L L 1 a, 60kg C @p 6,

T 4: 63 3 :1 [3 z .5 0' 3 E 6' 6' m? 2 6' a C 0 7 7% f. Pfzffner INVEN T0)" Patented July 5, 1932 UNITED STATES PATENT OFFICE EMIL PEIIFNER, O1?" FRIBOURG, SWITZERLAND, ASSIGNOR, BY MESNE ASSIGNMENTS, TO RADIO PATENTS CORPORATION, OF NEW YORK, N. Y., A CORPORATION OF NEW YORK , LINE PROTECTING AND MESSAGE TRANSMITTING SYSTEM Appllcaflon filed January 28, 1926, Serial No. 83,266, and in Germany March 8, 1925.

This invention relates to a system for carrier current transmission along electric power lines such as for transmitting messages by means of high frequency carrier currents. An object of the invention is to provide means for securing eificient coupling connection of the carrier current apparatus with the power Iine and protecting it, at the same time, against the high tension of the power currents flowing in the power line.

Another object of this invention is to provide a high frequency carrier current system associated with an electric transmission power line net-work in which interference of the high tension power currents and the high frequency carrier currents, is prevented.

A further object of my invention consists in using electrical condensers for the purpose of connectin the carrier current apparatus with a power me in such a manner as to allow these condensers to act simultaneously as a means for suppressing excess power volt-ages without interfering or being interfered with the operation of the carrier current system.

Still a further object of my invention is to produce a carrier current apparatus which is very simple in design and operation and WlllCh is very flexible in its use.

These and further objects of my invention will become apparent by the following description taken in conjunction with the accompanying drawing which show circuit diagrams illustrating the invention. 7

Generally three arrangements are employed for transmitting messages through electric transmission lines by means of directed waves, namely transmitting stations, receiving stations and bridging plants for passing the message transmitting high-frequency waves around places of the network, which prevent the passage of high-frequency currents, for instance reactances, transformers and the like. a

Now condensers and particularly high pressure condensers are employed for passing the high-frequency currents, produced by the transmitter, into the line charged with low-frequency workingvoltage, further for passing these high-frequency currents from the same line into the receiver and finally for bridging high-frequency difficulties.

If it is desired to simultaneously use these condensers as excess voltage apparatus, one terminal of the same has to be grounded in order to permit the high-frequency excess voltage to freely pass to the ground. Therefore the transmitting and receiving apparatus are not to be connected in series with the capacity, because its reactance would be an obstacle to the discharge.

There drawbacks are removed by the arrangement according to the present invention.

Three connecting diagrams according to the present invention are shown by way of example in Figs. 1, 2 and 3 of the accompanying sheet of drawings.

Taken for instance that two lines 1 and 1 are connected with one another by a trans-.

former T, and it is desired to transmit messages from the beginning of the line, 1 to the end of the line 1 by means of high-frequency waves and to protect against excess voltages both lines simultaneously by means of condensers CI, CII, CIII, CIV, each consisting of members C ,'C1, C C and C, connected in series. 7 i c The transmitting apparatus S operates a resonance circuit, consisting of a member C of the condenser CI which comprises a battery of series connected condensersC C C C and C, and an induction coil L formed for instance by the secondary coil of a highfrequency transformer L L The resonance-tensions produced in the condenser C are transmitted to the line 1 by the members C C C C The same or any other known connection is applied to the receiver E at the end of the line 1 Now the condensers CII, CIII for bridging the transformer T may be coupled with each other by high-frequency transformers L L L L5 as shown in Fig. 1, or by a coupling condenser C as illustrated in Fig. 2, or by a conductive connection a of a certain ohmic resistance or reactance as shown 1n Fig. 3.

I claim 1. A combined system for protecting power conductors from excess voltages and for enabling high frequency signals to be transmitted, including a condenser connected between one of said conductors and ground, said condenser having series-connected units and serving to protect said conductor against excess voltages, and coupling means for high frequency signals connected across a fractional part 0 aid protective condenser.

2. A combined system for protecting power conductors having a transformer interposed therein, from excess voltages and for enabling high frequency signals to be transmitted, including a condenser connected be tween one of said conductors and ground, on one side of said transformer, said condenser having units connected in series and serving to protect said conductor against excess voltages, a second similar condenser connected between a conductor on the other side of said transformer and ground, coupling means for high frequency signals connected across a fractional part of said first mentioned condenser coupling means for high frequency signals connected across a fractional part of the capacit of said second mentioned condenser, an means for by-passing high frequency signals around said transformer from one coupling means to the other.

3. A combined system for protecting power conductors having a transformer interposed therein, from excess voltages and for enabling high frequency signals to be transmitted, including a plurality of electrical condensers connected between one of said conductors and ground on one side of said transformer, each of said condensers having condenser units connected in series and serving to protect said conductor against excess voltages, aplurality of similar condensers connected between another conductor and ground on the opposite side of said transformer, high frequency signals coupling means connected across a fractional part of one of said first mentioned condensers, high frequency signal couplin means connected across a fractional part 0. one of said second mentioned condensers, and high frequency signal coupling means acting between fractional parts of others of said first and second mentioned condensers :to serve as a bypass for high frequency signals around said transformer.

4. A combined system for protecting power conductors from excess voltages and for enabling high frequency signals to be transmitted, including a condenser connected be tween one of said conductors and ground, said condenser having series-connected units and serving to protect said conductor against excess voltages, and coupling means for high frequency signals including an inductance coilassociated with said condenser units to utilize them for the aforesaid signalling puroses. P 5. A combined system for protecting power conductors from excess voltages and for enablin high frequency signals to be transmitte including a by-pass line connected between one of said conductors and ground and having interposed therein a series of condenser units to protect said conductor against excess voltages, and coupling means for high frequency signals including an inductance coil utilizing a fractional part of said by-pass adjacent to ground for the aforesaid signalling purposes.

6. A combined system'for protecting power conductors from excess voltages and for enabling high frequency signals to be trans mitted, including a condenser connected between one of said conductors and ground, said condenser having series connected units and serving to protect said conductor against excess voltages, and coupling means for high frequency signals connected with said condenser to utilize a fraction of the voltage drop between said conductor and ground.

In testimony whereof I afiix my signature.

. EMIL PFIFFNER. 

